ARRT Lower Extremity Procedures 3 — Questions and Answers
Question 1: For an AP projection of the toes, the central ray is directed perpendicular to the IR at which point?
- The base of the third metatarsal
- The third metatarsophalangeal joint (Correct answer)
- The midshaft of the third proximal phalanx
- The distal interphalangeal joint of the third toe
Correct answer: The third metatarsophalangeal joint
The CR is directed perpendicular to the IR at the third MTP joint, centering the image on the toe joints of interest.
Question 2: During a stress inversion projection of the ankle, which ligament injury is being evaluated?
- Deltoid ligament
- Anterior tibiofibular ligament
- Lateral collateral ligament complex (ATF, CF, PTF) (Correct answer)
- Spring ligament
Correct answer: Lateral collateral ligament complex (ATF, CF, PTF)
Inversion stress testing evaluates the lateral collateral ligament complex, primarily the anterior talofibular and calcaneofibular ligaments.
Question 3: For the plantodorsal (axial) projection of the calcaneus, the central ray is angled approximately how many degrees cephalad to the long axis of the foot?
- 10 degrees
- 20 degrees
- 40 degrees (Correct answer)
- 60 degrees
Correct answer: 40 degrees
The CR is angled 40 degrees cephalad to the long axis of the foot to project the calcaneus in the axial plantodorsal view.
Question 4: For a true AP projection of the hip, the lower limb is rotated internally approximately how many degrees to place the femoral neck parallel to the IR?
- 5 degrees
- 10 degrees
- 15 degrees (Correct answer)
- 25 degrees
Correct answer: 15 degrees
Internal rotation of 15 degrees corrects for the normal anteversion of the femoral neck, placing it parallel to the IR and reducing foreshortening.
Question 5: Which projection is used to best evaluate the patellofemoral joint space for chondromalacia patellae?
- AP projection of the knee
- Lateral projection of the knee
- Tangential (sunrise/skyline) projection of the patella (Correct answer)
- PA axial projection (tunnel view)
Correct answer: Tangential (sunrise/skyline) projection of the patella
The tangential (sunrise or Merchant) projection profiles the patellofemoral joint, evaluating patellar tracking and cartilage integrity.
Question 6: For the AP oblique projection of the ankle in medial rotation (mortise view), the foot and leg are rotated medially how many degrees?
- 10 degrees
- 15-20 degrees (Correct answer)
- 30 degrees
- 45 degrees
Correct answer: 15-20 degrees
A 15–20 degree medial rotation produces the mortise view, placing all three sides of the ankle mortise (tibiotalar joint) in profile.
Question 7: The Settegast projection is used to evaluate which structure of the knee?
- Intercondylar fossa
- Tibial plateau
- Patella in the tangential plane (Correct answer)
- Proximal tibiofibular joint
Correct answer: Patella in the tangential plane
The Settegast method is a tangential projection of the patella performed with acute knee flexion to profile the patellofemoral articulation.
ARRT Lower Extremity Procedures 3
For an AP projection of the toes, the central ray is directed perpendicular to the IR at which point?